Q. Debating with an editor over capitalization of the word bicentennial. When it’s an adjective (“bicentennial year”), I agree that no cap is needed, but I contend that when it’s a noun (“the Bicentennial”), a cap is needed. Agree—or not?

A. The noun bicentennial, like anniversary or birthday or even golden jubilee, is normally lowercased. But if you’re referring to a specific bicentennial, like the one the United States celebrated in 1976—“the Bicentennial”—a capital B might be warranted. Or so it seems in hindsight.

According to a Google Ngram comparison of the lowercase b and capital B forms of the word, there have been three notable jumps for “Bicentennial” in books published in English since 1900:

The two biggest bumps align with major bicentennials in the US (1976) and France (1989). The third peak—ca. 1932—corresponds to the bicentennial of George Washington’s birthday. (The ngram doesn’t tell you any of this—and there are other possibilities—but it’s fun to guess.)

In a publication that discusses one of the national bicentennials, a capital B would make sense. But note that both nouns and adjectives would qualify: the US Bicentennial, the Bicentennial celebrations in the US.